For many years, the problem of disposability has plagued industries that provide disposable products such as diapers, wet wipes, adult incontinent garments and feminine care products. While much headway has been made in addressing this problem, one of the weak links has been the inability to create an economical coherent fibrous web which will readily dissolve or disintegrate in water but still have sufficient in-use tensile strength.
Binder compositions have been developed which can be more dispersible and are more environmentally responsible than past binder compositions. One class of binder compositions includes polymeric materials having inverse solubility in water. These binder compositions are insoluble in warm water, but are soluble in cold water, such as found in a toilet. It is well known that a number of polymers exhibit cloud points or inverse solubility properties in aqueous media. These polymers include: (1) evaporation retarders; (2) temperature sensitive compositions, which are useful as temperature indicators due to a sharp color change associated with a corresponding temperature change; (3) heat sensitive materials that are opaque at a specific temperature and become transparent when cooled to below the specific temperature; (4) wound dressings with good absorbing characteristics and easy removal; and, (5) materials in flushable personal care products.
Other binders include a class of binders which are ion-sensitive. In some cases, terpolymers are used as binders for flushable nonwoven webs. The acrylic acid-based terpolymers, which comprise partially neutralized acrylic acid, butyl acrylate and 2-ethylhexyl acrylate, may be used as binders for use in flushable nonwoven webs in some parts of the world. However, because of the presence of a small amount of sodium acrylate in the partially neutralized terpolymer, such binders fail to disperse in water containing more than about 15 ppm Ca2+ and/or Mg2+. When placed in water containing more than about 15 ppm Ca2+ and/or Mg2+ions, nonwoven webs using the above-described binders maintain a tensile strength greater than 30 g/in., which negatively affects the “dispersibility” of the nonwoven web. The proposed mechanism for the failure is that each calcium ion binds with two carboxylate groups either intramolecularly or intermolecularly. Intramolecular association causes the terpolymer chain to coil up, which eventually leads to polymer precipitation. Intermolecular association yields crosslinking. Whether intramolecular or intermolecular associations are taking place, the terpolymer is not soluble in water containing more than about 15 ppm Ca2+ and/or Mg2+. Due to the strong interaction between calcium ions and the carboxylate groups of the terpolymer, dissociation of the complex is highly unlikely because this association is irreversible. Therefore, the terpolymer that has been exposed to a high Ca2+ and/or Mg2+ concentration solution will not disperse in water even if the calcium concentration decreases. This limits the application of the terpolymer as a flushable binder material because most areas across the U.S. have hard water, which contains more than 15 ppm Ca2+ and/or Mg2+.
Other binders, while being in contact with an organic solvent, usually as a cleaning agent or a preservative, still require the presence of ions, such as monovalent or divalent metal ions, to establish sufficient stability during use and dispersibility at disposal. As discussed above, the issue of hard water may again apply to such binders.
In some dispersible cleaning or personal care products, such as a water-disintegratable cleansing sheet; i.e., wet wipe, comprising water-dispersible fibers treated with a water-soluble binder having a carboxyl group. The cleansing sheet is treated with a cleansing agent containing 5%-95% of a water-compatible organic solvent and 95%-5% water. The organic solvent is typically propylene glycol. The cleansing sheet retains wet strength and does not disperse in the organic solvent-based cleansing agent, but disperses in water. The cleansing sheets must have higher concentrations of organic solvents as these solvents ensure the in-use wet strength for the cleansing sheets. Without the solvents, the cleansing sheets would have little in-use wet strength and would not be effective as a wet wipe. However, the use of such high amounts of organic solvent results in a greasy after-feel when the cleansing sheet is used, and these organic solvents may cause discomfort and irritation to skin or mucosa in higher amounts.
The presence of harmful or unwanted microorganisms on the skin or mucosa can be a significant problem, resulting in discomfort or more serious health issues. By way of example, many women during their lives will suffer from a vaginal bacterial or fungal infection. These infections can occur for a variety of reasons. For example, the use of antibiotics may result in the overgrowth of Candida albicans, resulting in the condition known as vuvlovaginitis (vulvovaginal Candidiasis or VVC). This condition is typically treated by azole anti-fungal agents, applied intravaginally or orally. Some sufferers may believe their vaginal infection is a fungal infection when it is actually a bacterial infection. Common remedies for vaginal fungal infections are largely ineffective against vaginal bacterial infections, and the use of over-the-counter anti-fungal products may actually mask the bacterial infection. These bacterial infections are known as “bacterial vaginosis,” and are much more common than VVC. Clinically, bacterial vaginosis is a polymicrobial vaginal infection caused by an increase in the number of anaerobic organisms with a concomitant decrease in the Lactobacilli in the vagina.
In normal conditions the predominant organism in the vagina, Lactobacilli, regulates the growth of anaerobes and other bacteria through the production of hydrogen peroxide and lactic acid from vaginal glycogen, in order to maintain vaginal acidity. It is, therefore, important that compositions and products intended for use on or around the vulvovaginal skin or mucosa do not adversely affect the population of Lactobacilli and that permit a healthy vaginal pH to be maintained.
Treatments for VVC and bacterial vaginosis known in the art generally relate to novel anti-fungal and anti-bacterial chemical compounds and penetration-enhancing formulations. Often these compounds involve the use of organic solvents, such as ethyl alcohol, in combination with other organic solvents to solubilize the anti-fungal and anti-bacterial compounds. However, these organic solvents can be irritating to the vulvovaginal skin or mucosa.
There are numerous personal cleansing products with a multitude of formulations and uses. However, when many personal hygiene products are contacted with the body, there is frequently a perception of cold. When an individual contacts the skin or mucosa with the product, the individual may experience an unpleasant or uncomfortable cold feeling due to the difference in temperature between the body and the ambient temperature of the product.
A variety of compositions are known in the art or described in the literature that claim to impart a warming sensation when applied to the skin or mucosa. Many of these compositions contain plant extracts or other compounds which are irritating to the skin or mucosa, and the associated feeling of warmth is by virtue of their irritant action. Other compositions claim to enhance blood flow in order to cause tissue warming. Still others purportedly work on the principle of freezing point depression, and rely on heating in the microwave or cooling in a refrigerator. Another cosmetic composition contains self-heating properties through a compound possessing a boron-oxygen-boron linkage, which reacts exothermically with water. However, none of these compositions combine a non-irritating, non-toxic warming composition with a disposable, dispersible cleaning or personal care product.
There exists a need for dispersible cleaning or personal care products possessing softness, flexibility, three dimensionality, and resiliency; wicking and structural integrity in the presence of aqueous or bodily fluids; and, true fiber dispersion after toilet flushing so that the cleaning or personal care product does not become entangled at obstructions, such as with tree roots or at bends in sewer pipes. Moreover, there is a need in the art for flushable cleaning or personal care products having water-dispersibility in all areas of the world, including soft and hard water areas. Furthermore, there is a need for water-dispersible binders that do not reduce wettability of the cleaning or personal care product with which they are used and are sprayable for relatively easy and uniform application to and penetration into the cleaning or personal care products. Finally, there is a need for water-dispersible, flushable wet wipes that are stable during storage and retain a desired level of wet strength during use when wetted with the appropriate cleaning, disinfection, or sanitizing wetting composition. Such a cleaning or personal care product is needed at a reasonable cost without compromising product safety and environmental concerns, something that past products have failed to do.
There is also a need for a cleaning or personal care product possessing the above properties that contains warming compositions which are non-toxic and non-irritating to impart a warming, soothing sensation, or increase blood circulation as a consequence of the warming, to the skin or mucosa when applied thereon.
Additionally, there is a need for a cleaning or personal care product that possesses the above properties that has the ability to act as a vehicle to deliver anti-microbial, pharmaceutical or treatment agents to the skin or mucosa when applied thereon.